Deuce

The Kelts called wood-demons dus. (Compare the Latin
deus.)

“In the popular mythology both of the Kelts and Teutons there were
certain hairy
wood-demons, called by the former dus, and by the latter
scrat (? scratz). Our common names of `Deuce' and `Old Scratch' are
plainly derived from these.” —Lowell: Among my

Books

(Witchcraft), p. 109.

It played the deuce with me.

It made me very ill; it disagreed with me; it almost ruined me.
The deuce is in you. You are a very demon.

Deuce take you.

Get away! you annoy me. What the deuce is the matter? What
in the world is amiss?